Microtubular systems have been implicated, morphologically and by the use of microtubular-active agents, in intracellular transport of membrane-bound organelles. The purpose of this proposed study is to show that the cytopharyngeal ribbons of Paramecium, a system of microtubules, is involved in moving membrane-bound vesicles from the cytoplasm and the cytoproct to the oral region. Apparently these vesicles originate from the cytoproct and cytoplasm by pinocytosis of the food vacuole membranes and are transported to the oral region where they are to be reused to form new food vacuole membranes. We also hope to discover to what extent the microtubules may provide the motive force for this movement. Our project will include a study of the normal morphogenesis of the oral region as well as a study of the normal development and regeneration of the cytoproct following microsurgery to determine the origins of microtubular systems. An exhaustive search for connections between microtubules and vesicles will be made and possible ATPase activity along the microtubules will be investigated cytochemically. Model systems will be made in an attempt to show vesicle movement in vitro along microtubules after adding an energy source. Then the microtubules and vesicles will be biochemically isolated and reconstituted in the presence of a reactivation solution in an attempt to show which structures are essential to produce movement of membrane-bound particles. Cinematography will be used to record any movement. Endocytosis at the cytoproct will be studied using heavy meromyosin and cytochalasin B. BIBLIOGRAPHIC REFERENCES: Hausmann, K. and R. D. Allen. 1977. Membrane and microtubules of the excretory apparatus of Paramecium caudatum. Cytobiologie, in press. Allen, Richard D. 1977. Intramembrane alterations that occur in digestive vacuoles of Paramecium. Proc. Vth Int. Cong. Protozool., in press.